Present day assault rifles, such as the “AR-15” assault rifle, have upper assemblies that employ rear-mounted actuation handles to cycle the actions (e.g. the firing pin and pin carrier) of AR-15 rifles. Typically, the rear-actuation handle is “T” shaped and is installed at the top of the upper assembly housing, below a modular rail or carry handle. The rear-mounted actuation handle engages the bolt carrier when it is pulled toward the butt-plate of the rifle stock. In order to cycle the action (operate the AR-15 rifle), this configuration requires that there be sufficient clearance between the rear-mounted actuation handle and any optic, or other accessory that may be installed on the modular rail or carry handle. Such configurations also prevent a user from cycling the action when the AR-15 rifle is shouldered in a firing position. Therefore, a longstanding need exists to provide for an actuation handle installed on the side of the upper assembly of an AR-15 rifle (or an “M-16”, an AR-15 variant, and other like assault rifles and firearms).